One of the problems of the presently available spray booms for aerial crop spraying is that they are generally not adjustable in flight. As a result, the pilot must select the boom and nozzles appropriate for the weather conditions at the time and set the nozzle angle and other parameters prior to take-off. In order to achieve reasonably efficient spraying, he must be able to accurately estimate wind speed, temperature and humidity at the crop location and. then set the spraying equipment to suit the estimate for those particular conditions. Even if a pilot is extremely accurate with his estimates, air conditions change over the spraying time and additionally aircraft speed generally increases as the payload decreases. Further, wind speed can differ substantially from a forward, run to a backward run. In this respect it will be appreciated that wind speed at the spray nozzles has a significant effect on droplet size which in turn affects drift and crop coverage. Another one of the problems associated with aerial crop spraying is that crosswinds have a significant effect on the spray deposition pattern due to the wing tip vortices.
One object of the present invention is to ameliorate one or more of the aforementioned problems. Another object is to provide spray booms which are more efficient in use. Another object is to provide a method of aerial spraying which allows for more effective crop coverage and less harmful drift and equipment for carrying out the method.